Dave G. found the nice brass regulator leaking, on the LCW line that goes to the Arc/BSY from Hall A. It is against the wall by the stairs up to the beamline balcony. We talked to Carroll Jones and he suggested we just shut the valves on the supply and the return lines since they had changed the LCW routing in the Arc/BSY and no longer used LCW from Hall A. I shut off the valves on the supply and return lines. I put a red out of service tag on the regulator. When I shut the valve on the supply line the pressure dropped VERY slowly. My guess is that with the downstream valves closed in the Arc/BSY the pressure on the downstream side of the regulator was higher than the upstream side, when LCW was shut off to do this bypass. The reverse pressure differential would seem to have done some damage to the regulator.